Pseudoxanthobacter liyangensis sp. nov., isolated from dichlorodiphenyltrichloroethane-contaminated soil.

An aerobic, Gram-stain negative, pale, rod-shaped, nitrogen-fixing bacterial strain, DDT-3(T), was isolated from dichlorodiphenyltrichloroethane-contaminated soil in Liyang, PR China. Strain DDT-3(T) grew at temperatures ranging from 20 to 40 °C (optimum 30-37 °C) and a pH of between 5.0 and 10.0 (optimum pH 7.0-8.0). The G+C content of the total DNA was 70.1 mol%. The 16S rRNA gene sequence of strain DDT-3(T) showed the highest similarity to that of Pseudoxanthobacter soli CC4(T) (99.6%), followed by Kaistia dalseonensis B6-8(T) (93.3%), Kaistia soli 5YN9-8(T) (93.0%) and Amorphus orientalis YIM D10(T) (93.0%). Strain DDT-3(T) showed less than 92.6 % similarity with other species of the family Xanthobacteraceae. The major cellular fatty acids of strain DDT-3(T) were C19:0 cyclo ω8c (42.6%), C16:0 (33.2%) and C18:1ω7c (10.0%). The only respiratory quinone was ubiquinone Q-10. The characteristic diamino acid of the peptidoglycan was meso-diaminopimelic acid. The major polar lipids were glycolipid, lipid, phosphatidylcholine, aminolipid, phosphatidylmethylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The polyamine profile consisted of major amounts of putrescine (92.9%) and minor amounts of spermidine (5.0%) and spermine (2.1%). These chemotaxonomic data support the affiliation of strain DDT-3(T) with the genus Pseudoxanthobacter. The DNA-DNA hybridization value between strain DDT-3(T) and strain CC4(T) was 47.8% (reciprocal 44.3%). DNA-DNA hybridization data as well as the biochemical and physiological characteristics strongly supported the genotypic and phenotypic differentiation of strain DDT-3(T) and strain CC4(T). Strain DDT-3(T), therefore, represents a novel species of the genus Pseudoxanthobacter, for which the name Pseudoxanthobacter liyangensis sp. nov. is proposed. The type strain is DDT-3(T) ( = KACC 16601(T) = CCTCC AB 2013167(T)).